Workpiece locating apparatus for use in multi-wheel grinding machines

ABSTRACT

In a workpiece locating apparatus for working a plurality of spaced apart portions by means of a multi-wheel grinding machine, respectively defined between a pair of surfaces of said workpiece, for example crank-pins of a crankshaft there are provided a plurality of spaced apart locator heads respectively confronting the portions to be worked, mechanisms for moving the locator heads towards and away from the portions to be worked and a mechanism for simultaneously rotating the locator heads. The locator heads are inserted between the surfaces of respective pairs when moved towards the portions to be worked and are urged against one of the surfaces when rotated.

[ 51 Sept. 12, 1972 United States Patent Ohta [54] WORKPIECE LOCATINGAPPARATUS 2,723,504 11/1955 Alvord...................51/105 SP FOR USEIN MULTI-WHEEL GRINDING MACHINES Happe1.................. 7/1963 Foumier..................51/165 R [72] Inventor: Hiroshi Ohta, Kariya, Japan[73] Assignee: Toyoda Koki Kabushiki Kaisha,

Primary ExaminerHaro1d D. Whitehead Attorney-Wenderoth, Lind & Ponack[57] ABSTRACT In a workpiece locating apparatus for workingv a plu- [22]Filed:

reality of spaced apart portions by means of a multiwheel g rindingmachine, respectively defined between pair of surfaces of saidworkpiece, for example [52] US. Cl. ..,.......,.....5l/105, 51/165 R,51/237 CS [51] Int. Cl. 5/42 .51/105 SP, 165 R, 237 CS crank-pins of acrankshaft there are provided a plurality of spaced apart locator headsrespectively con- [58] Field of Search 1 fronting the portions to beworked, mechanisms for References cued moving the locator heads towardsand away from the UNITED STATES PATENTS portions to be worked and amechanism for simultaneheads. The locator heads are ously rotating thelocator n e m m d n m d Pam w i r 0 w d o r r e n u Wem .W mbw F g mmw im c r aiiw D nfi 4 u m f mh 0 m n e 1 S C 0 5 w my w. .mm m. dda mg m om .m m u PPPPP SSSSS 55555 00000 11111 11111 .5 .55 m M e t" mm a n Mkde wm MHMFS 444 35555 99999 11111 771111 111 3 0 2 03666 39333 5999 Q2222 PATENTEDsmzmz 3.690.070

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' SHEET 3 BF 3 INVENTOR 1M 042 B law/Ma gy ATTORNEY WORKPIECE LOCATINGAPPARATUS FOR USE IN MULTI-WHEEL GRINDING MACHINES BACKGROUND OF THEINVENTION This invention relates to a workpiece locating apparatus for amulti-wheel grinding machine and more particularly to a workpiecelocating apparatus for a multi-wheel grinding machine for simultaneouslygrinding two crankpins of a crankshaft for example.

When locating or positioning a workpiece such as a crankshaft on agrinding machine there are generally used two methods. According to onemethod a surface of the workpiece to be ground is used as the referencesurface whereas in the other, a surface not to be ground is used as thereference surface. However, in a grinding machine designed tosimultaneously work two crankpins, because it is impossible to work byutilizing the former method it has been the practice to use the lattermethod. For this reason, unless the accuracy of the previously workedsurface or unworked surface is high, the previously worked surface orunworked surface to be ground will not coincide so that some portions ofthe workpieces will be left unworked or the loads on two grinding wheelswill become unbalanced thus lowering the accuracy of the working.

SUMMARY OF THE INVENTION It is therefore an object of this invention toprovide a novel workpiece locating apparatus wherein a plurality ofportions of a workpiece are. accurately located by utilizing surfaces ofthe workpiece to be ground.

Another object of this invention is to provide a novel workpiecelocating apparatus suitable for use in working a plurality of spacedapart crankpins of crankshafts by means of a multi-wheel grinding wheelwherein respective crankpins to be worked are accurately positioned withrespect to respective grinding wheels so as to balance the loads on thegrinding wheels thus eliminating an axis load from being applied on thegrinding wheels.

Briefly stated, in accordance with this invention there is providedworkpiece locating apparatus for working a plurality of spaced apartportions by means of a multi-wheel grinding machine, respectivelydefined between a pair of surfaces of the workpiece said apparatuscomprising a plurality of spaced apart locator heads, each confrontingeach one of the grinding wheels, and mechanism for moving the locatorheads towards and away from the portions to be worked and a mechanismfor simultaneously rotating the locator heads. The locator heads areinserted between the surfaces of respective pairs when they are movedtowards the portions to be worked and are urged against one of thesurface when rotated.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a longitudinal sectional view of the workpiece locatingapparatus embodying this invention;

FIG. 2 is a sectional view taken along a line II-II in FIG. 1;

FIG. 3 is a sectional view taken along a line III-III in FIG. 1 and FIG.4 is a plan view to show the operating positions of the locator headswhen positioned between crank arms.

DESCRIPTION OF THE PREFERRED EMBODIMENT The workpiece locator shown inthe accompanying drawing comprises a frame 1 secured to a bed 5 and amain body 2 secured to the frame and having a pair of elevatingmechanisms 4 and a pair of rotating mechanisms 5 for locator heads 3.Since the constructions of the pairs of elevating mechanisms 4 androtating mechanisms 5 are the same corresponding parts of the pairs aredesignated by the same reference numerals.

With reference to the lefthand elevating mechanism 4 it comprises avertical cylinder 6 formed in the elevating mechanism 4 of the main body2, a piston 7 slidably received in the cylinder 6 and a piston rod 8extending through a piston cap 9 and a cap 10 mounted on the upper endof the cylinder. The locator head 3 is mounted on the upper end ofpiston rod 8. A pair of pressurized oil ports 11a and 11b are formed inthe upper and lower portions of the cylinder 6, respectively, said ports11a and 11b being communicated with a source of pressurized oil (notshown) via a change over valve (not shown) and oil passages 12a and 12b.

As best shown in FIG. 2, the lefthand rotating mechanism 5 comprises ahollow shaft 13 slidably extending through the centers of piston rod 8and piston 7 of the elevating mechanism 4.

The shaft 13 has a key slot thereon for receiving a key 14, while acorresponding key way 8a is cut in the piston rod 8. The key 14 isaxially slidably engaged in the key way 8a.

The shaft 13 is coupled to the piston rod 8 through the key 14 fortransmitting the torque from shaft 13 to piston rod 8. Shaft 13 slidablyand sealingly extends through a lower piston cap 15 and is rotablyjoumalled in a lower cylinder cap 16, and a pinion 17 is secured to theouter end of shaft 13. As shown in FIG. 3, beneath cylinder 6 isprovided a transverse cylinder 18 in the main body 2, and a piston 19 isslidably received in cylinder 18 and has a rack 20 on one side meshingwith pinion 17 secured to the shaft 13. As shown in FIG. 1 on both sidesof piston 19 are formed pressurized oil ports 20a and 21 which areconnected with the source of pressurized oil (not shown) via oilpassages 22 and 23 and a change-over valve (not shown). A rod 24 isconnected to the lefthand end of righthand piston 19, as viewed in FIG.1, the rod 24 slidably extending through cylinder cap 26 on the left endof the righthand cylinder 18 of the righthand rotating mechanism 5 andbeing connected with the righthand end of the lefthand piston 19 throughcylinder cap 25, thus interconnecting both pistons 19 in the left andrighthand rotating mechanisms 5. Arod 27 slidably extending through alefthand cylinder cap 26 is connected to the lefthand end of lefthandpiston 19 of the lefthand rotating mechanism 5, and a pair of dogs 28and 29 are secured to the outer end of rod 27. On the opposite sides ofdogs 28 and 29 are provided a limit-switch 30 for confirming themovement of the locator heads 3 to the original position and alimit-switch 31 for confirming the movement of the locator heads 3 tothe rotated position. when dog 28 or 29 engage the operating lever 30aor 31a of the limit-switches 30 and 31, these limitswitches operate toclamp a workpiece 49 which is slidably mountedon eccentric chucks 52secured to the spindles which are rotatably mounted on headstocks 53 ofthe grinding machine, or to actuate the elevating mechanism 4 to lowerthe locator heads 3.

The righthand rotating mechanism 5 is not provided with above describedcontrol mechanism including oil passages 22 and 23, control rod 27, andlimit-switches 30 and 31.

A shaft 32 of an elevating motion confirming mechanism forming a part ofthe elevating mechanism 4 is freely received in the hollow shaft 13 ofthe rotating mechanism 5, as shown in FIG. 2. Upward movement of shaft32 is limited by a collar 50 secured to the top of the shaft 32 andengaging a shoulder 8d on the upper portion of piston rod 8. An innerbore 8b in the piston rod 8 is slightly larger than the shaft 13, alonga predetermined length. The diameter of collar 50 is smaller than thediameter of the bore 81;. Thus, when the piston rod 8 is raised untilthe shoulder 8c of the bore 8b engages collar 50, shaft 32 will beraised by shoulder 8cthrough collar 50.

To the extreme lower end of shaft 32 beyond pinio 17 is connected afirst lever 33 by a pivot pin 34. The first lever is slidably connectedto a second lever 35 which is connected to a third lever 37 through apivot pin 36 rotatably mounted on the frame 1 (not shown). Bifurcatedend 37a of the lever 37 engages a pin 39 secured to one end of a controlshaft 38 which is slidably supported by spaced apart supports 41 securedto a base 40 housed in the frame 1 for mounting limitswitches. Shaft 38also carries a pair of dogs 42 and 43 for operating a limit-switch 44for confinning the downward movement and a limit-switch 45 forconfirming the upward movement through operating levers 44a and 45a ofthese limit-switches. When the locator head 3 reaches its loweredposition or raised position, limit-switch 44 or 45 is operated toconfirm completion of the lowering or raising operation of the locatorheads 3 and then to advance the grinding wheel carriage or to operatethe rotating mechanisms 5. A spring 46 is connected between righthanddog 43 and limit-switch base 40 to normally bias the control shaft 38toward the left.

Locator heads 3, as shown in FIG. 4 are in the form of elliptical camsand have the same configuration. And further those heads arepoint-symmetrically located with respect to a point A of intersection ofthe axes of the crankpins 49 and the center-line between the locatorheads 3.

Just above respective locator heads 3, there are provided a pair ofgrinding wheels 47. As shown in FIG. 1, crankpins 49 to be ground on thecrankshaft 48 are supported between grinding wheels 47 and locator heads3 by well-known means, not shown.

In operation, when locator heads 3 are in their lowered position asshown by solid lines in FIG. 1, pressurized oil is supplied to the lowerside of pistons 7 through passages 12b, and oil port 11b to raisepistons 7 and locator heads 3. At this time, locator heads 3 arepositioned so that their longitudinal axes are at an angle of 90 withrespect to the axes of crankpins 49 whereby the locator heads 3 areinserted between pairs of shoulders of crankpins 49.

As the locator heads 3 are raised, shoulder 8c at the bottom of bore 8!;in the piston rod 8 comes into abutment with collar 50 to raise shaft 32of the mechanism for confirming up and down motions. Thus, first andsecond levers 33 and 35 are raised to rotate third lever 37 in theclockwise direction as viewed in FIG. 2 whereby limit-switch 45 forconfirming the upward movement is operated by shaft 38 and dog 43. Thus,the upward motion of pistons 7 is stopped when locator heads 3 arebrought very close to pins 49 as the upper ends of pistons 7 engage caps9.

Further, the limit-switch 45 operates to admit pressurized oil to therighthand side of piston 19 in lefthand cylinder 18 through passage 23and oil port 21 to move piston 19 to the left whereby pinion 17 isrotated by rack 20 to rotate hollow shaft 13. The rotation of thishollow shaft is transmitted to locator head 3 through piston rods 8.When piston 19 in the lefthand cylinder 18 is moved to the left as abovedescribed, piston 19 in the righthand cylinder 18 is also moved in thesame direction through connecting rod 24 thus causing the righthandlocator head 3 to rotate in the same direction concurrently with thelefthand locator head 3. As both locator heads 3 are rotated in thismanner, one side corner at the larger diameter end of each engages theinner surface of the outside shoulder 49a, thus setting the axialposition of the crankshaft 49 as shown in FIG. 4. The opposite sides ofthe large diameter ends are charnferred so that they will not engage theinner surface of the inner shoulders.

Concurrently therewith, the lefthand dog 29 on the control rod 27operates limit-switch 31 to clamp the workpiece 48 by the eccentricchuck mentioned above.

After positioning the pins 49 of the crankshaft 48, or

the workpiece and clamping thereof, a change-over valve, not shown, isoperated to-admit to pressurized oil into the lefthand chamber ofcylinder 18 to rotate heads 3 in the opposite direction to disengagethem from shoulders 49a. Then limit-switch 30 is operated to operateanother change-over valve, not shown, to

admit pressurized oil to the upper chambers in cylinders 6 thus loweringlocator heads 3. Then, the limitswitch 44 is operated by dog 42 to stoppistons 7 at their lowermost position shown in FIG. 1. Thereafter,grinding wheels 47 are advanced and crankshaft 48 is rotated forgrinding.

As above described, according to the locating apparatus of thisinvention, locator heads 3 are inserted between shoulders on theopposite sides of crankpins 49 and are then rotated whereby the locatorheads 3 are caused to engage shoulders adjacent the crankpins to beground for accurately positioning the crankshaft 48. Moreover, as thegrinding wheels 47 are positioned just above the locator heads, in otherwords, as the distance between the centers of the locator heads 3 andthe distance between the axial centers of the grinding wheels 47 areequal the respective centers of the gaps between respective shoulders49a are made to coincide with the axial centers of respective grindingwheels 47. Consequently, two pins 49 of the workpiece are workedaccurately at the same time. Moreover, as the positional errors of thepins with respect to the grinding wheels are eliminated there is noportion remaining unworked. Further, since equal loads are applied ontwo grinding wheels, no axial load is imposed on the grinding wheelshafts, thus assuring high accuracy workings.

It will be evident that many modifications and variations are possiblein light of the above teachings. It, therefore, is to be understood thatwithin the scope of the appended claims the invention may be practicedotherwise than as specifically described.

I claim:

1. A workpiece locating apparatus for a grinding machine having worksupport means for supporting and rotating a workpiece and a plurality ofgrinding wheels for effecting simultaneous grinding operations on aplurality of spaced portions of the workpiece, said spaced portionsrespectively having spaced shoulder portions, said workpiece locatingapparatus comprising, in combination, a frame for mounting on a bed ofthe grinding machine, a pair of spaced locator heads mounted on saidframe confronting two of said grinding wheels, said locator heads beingmovable between retracted positions and operative positions adjacent tothe spaced portions of the workpiece and being rotatable on axesrespectively perpendicular to the axes of the spaced portions of theworkpiece, said locator heads being disposed so that the midpointbetween the axes of rotations of the locator heads coincides with themidpoint between said two grinding wheels, means coupled to said locatorheads for moving said locator heads between said retracted positions andoperative positions, and means coupled to said rotator heads forsynchronously rotating said locator heads at operative positions so thateach locator head engages the shoulder portion of the workpiece at oneside thereof axially to position the workpiece relative to the grindingwheels.

2. A workpiece locating apparatus for a grinding machine having worksupport means for supporting and rotating a workpiece and a plurality ofgrinding wheels for effecting simultaneous grinding operations on aplurality of spaced portions of the workpiece, said spaced portionsrespectively having spaced shoulder portions, said workpiece locatingapparatus comprising a pair of spaced locator assemblies for mounting ona bed of the grinding machine to confront two of said grinding wheels,each of said locator assemblies including a main body, a rod disposed inperpendicular relation with the workpiece and slidably rotatablyreceived in said main body, power means coupled to said rod for movingsaid rod between a retracted position and an operative position adjacentto the workpiece, a locator head secured to the top of the rod, and ashaft rotatably journalled in said main body being coaxially slidablyand non-rotatably mounted in said rod, and rotating means operativelyconnected to the shafts of said locator assemblies for synchronouslyrotating said shafts, rods and locator heads, said rods of the locatorassemblies being disposed so that the midpoint therebetween coincideswith the midpoint between said two grinding wheels, whereby each locatorhead at the operative position, when rotated engages the shoulderportion of the workpiece at one side thereof axially to position theworkpiece relative to the grinding wheels.

3. A workpiece locating apparatus as set forth in claim 2, wherein saidrotating means comprises a pair of pinions respectively coaxiallymounted on said shafts, a rack slidably received in said main body beingengaged with said pinions, and means coupled to said rack for movingsaid rack.

4. A workpiece locating apparatus as set forth in claim 2, wherein saidpower means comprises a piston integrally coaxially connected to saidrod, said main body having a cylinder therein in which said piston isslidably received in coaxial relation with said rod.

5. A workpiece locating apparatus as set forth in claim 2, wherein saidlocator assembly still further includes a confirming shaft slidablyrotatably coaxially received in said shaft, a collar larger than thediameter of the shaft being mounted on the confirming shaft at the oneend thereof extending beyond said shaft, said rod having a cylindertherein in which said collar is disposed, said cylinder having adiameter larger than that of the collar and having a shoulder at the endthereof so that the shoulder engages the collar to move the confirmingshaft at the end portion of the movement of the rod to the operativeposition, a pair of dogs operatively connected to said confirming shaftand a pair of detectors respectively confronting said dogs to confirmthe movements of the locator head to the retracted and operativepositions.

1. A workpiece locating apparatus for a grinding machine having worksupport means for supporting and rotating a workpiece and a plurality ofgrinding wheels for effecting simultaneous grinding operations on aplurality of spaced portions of the workpiece, said spaced portionsrespectively having spaced shoulder portions, said workpiece locatingapparatus comprising, in combination, a frame for mounting on a bed ofthe grinding machine, a pair of spaced locator heads mounted on saidframe confronting two of said grinding wheels, said locator heads beingmovable between retracted positions and operative positions adjacent tothe spaced portions of the workpiece and being rotatable on axesrespectively perpendicular to the axes of the spaced portions of theworkpiece, said locator heads being disposed so that the midpointbetween the axes of rotations of the locator heads coincides with themidpoint between said two grinding wheels, means coupled to said locatorheads for moving said locator heads between said retracted positions andoperative positions, and means coupled to said rotator heads forsynchronously rotating said locator heads at operative positions so thateach locator head engages the shoulder portion of the workpiece at oneside thereof axially to position the workpiece relative to the grindingwheels.
 2. A workpiece locating apparatus for a grinding machine havingwork support means for supporting and rotating a workpiece and aplurality of grinding wheels for effecting simultaneous grindingoperations on a plurality of spaced portions of the workpiece, saidspaced portions respectively having spaced shoulder portions, saidworkpiece locating apparatus comprising a pair of spaced locatorassemblies for mounting on a bed of the grinding machine to confront twoof said grinding wheels, each of said locator assemblies including amain body, a rod disposed in perpendicular relation with the workpieceand slidably rotatably received in said main body, power means coupledto said rod for moving said rod between a retracted position and anoperative position adjacent to the workpiece, a locator head secured tothe top of the rod, and a shaft rotatably journalled in said main bodybeing coaxially slidably and non-rotatably mounted in said rod, androtating means operatively connected to the shafts of said locatorassemblies for synchronously rotating said shafts, rods and locatorheads, said rods of the locator assemblies being disposed so that themidpoint therebetween coincides with the midpoint between said twogrinding wheels, whereby each locator head at the operative position,when rotated engages the shoulder portion of the workpiece at one sidethereof axially to position the workpiece relative to the grindingwheels.
 3. A workpiece locating apparatus as set forth in claim 2,wherein said rotating means comprises a pair of pinions respectivelycoaxially mounted on said shafts, a rack slidably received in said mainbody being engaged with said pinions, and means coupled to said rack formoving said rack.
 4. A workpiece locating apparatus as set forth inclaim 2, wherein said power means comprises a piston integrallycoaxially connected to said rod, said main body having a cylindertherein in which said piston is slidably received in coaxial relationwith said rod.
 5. A workpiece locating apparatus as set forth in claim2, wherein said locator assembly still further includes a confirmingshaft slidably rotatably coaxially received in said shaft, a collarlarger than the diameter of the shaft being mounted on the confirmingshaft at the one end thereof extending beyond said shaft, said rodhaving a cylinder therein in which said collar is disposed, saidcylinder having a diameter larger than that of the collar and having ashoulder at the end thereof so that the shoulder engages the collar tomove the confirming shaft at the end portion of the movement of the rodto the operative position, a pair of dogs operatively connected to saidconfirming shaft and a pair of detectors respectively confronting saiddogs to confirm the movements of the locator head to the retracted andoperative positions.